Advertisements
Advertisements
Question
If class mark is 10 and class width is 6 then find the class.
Advertisements
Solution
Let x be the upper class limit and y the lower class limit.
class mark = 10 ..[given]
class mark = `(x + y)/2`
10 = `(x + y)/2`
x + y = 20 ...(i)
class width = 6 ...[given]
x - y = 6 ....(ii)
Adding equation (i) and (ii)
x + y = 20
+ x - y = 6
2x = 26
x = `26/2`
x = 13
Putting the value x = 13 in equation (i),
x + y = 20
13 + y = 20
y = 20 -13
y = 7
∴ the class is 7-13.
APPEARS IN
RELATED QUESTIONS
For class interval 20-25 write the lower class limit and the upper class limit.
Complete the Following Table.
| Classes (age) | Tally marks | Frequency (No. of students) |
| 12 - 13 | `cancel(bb|bb|bb|bb|)` | `square` |
| 13 - 14 | `cancel(bb|bb|bb|bb|)` `cancel(bb|bb|bb|bb|)` `bb|bb|bb|bb|` | `square` |
| 14 - 15 | `square` | |
| 15 - 16 | `bb|bb|bb|bb|` | `square` |
| `bb(N = sumf = 35)` |
In the table given below, class-mark and frequencies are given. Construct the frequency table taking inclusive and exclusive classes.
| Class width | Frequency |
| 5 | 3 |
| 15 | 9 |
| 25 | 15 |
| 35 | 13 |
In a village, the milk was collected from 50 milkmen at a collection center in litres as given below:
27, 75, 5, 99, 70, 12, 15, 20, 30, 35, 45, 80, 77, 90, 92, 72, 4, 33, 22, 15, 20, 28, 29, 14, 16, 20, 72, 81, 85, 10, 16, 9, 25, 23, 26, 46, 55, 56, 66, 67, 51, 57, 44, 43, 6, 65, 42, 36, 7, 35.
By taking suitable classes, prepare grouped frequency distribution table.
If the classes are 0-10, 10-20, 20-30... then in which class should the observation 10 be included?
The monthly maximum temperature of a city is given in degree celcius in the following data. By taking suitable classes, prepare the grouped frequency distribution table
29.2, 29.0, 28.1, 28.5, 32.9, 29.2, 34.2, 36.8, 32.0, 31.0, 30.5, 30.0, 33, 32.5, 35.5, 34.0, 32.9, 31.5, 30.3, 31.4, 30.3, 34.7, 35.0, 32.5, 33.5, 29.0, 29.5, 29.9, 33.2, 30.2
From the table, answer the following questions.
- For how many days the maximum temperature was less than 34oC?
- For how many days the maximum temperature was 34oC or more than 34oC?
Given below are the marks obtained by 30 students in an examination:
| 08 | 17 | 33 | 41 | 47 | 23 | 20 | 34 |
| 09 | 18 | 42 | 14 | 30 | 19 | 29 | 11 |
| 36 | 48 | 40 | 24 | 22 | 02 | 16 | 21 |
| 15 | 32 | 47 | 44 | 33 | 01 |
Taking class intervals 1-10, 11-20, ....., 41-50; make a frequency table for the above distribution.
Construct the frequency distribution table from the following cumulative frequency table:
| Ages | No. of students |
| Below 4 | 0 |
| Below 7 | 85 |
| Below 10 | 140 |
| Below 13 | 243 |
| Below 16 | 300 |
(i) State the number of students in the age group 10 - 13.
(ii) State the age-group which has the least number of students.
Construct a frequency distribution table from the following cumulative frequency distribution:
| Class Interval | Cumulative Frequency |
| 10 - 19 | 8 |
| 20 - 29 | 19 |
| 30- 39 | 23 |
| 40- 49 | 30 |
Given below are the marks obtained by 30 students in an examination:
|
08 |
17 |
33 |
41 |
47 |
23 |
20 |
34 |
|
09 |
18 |
42 |
14 |
30 |
19 |
29 |
11 |
|
36 |
48 |
40 |
24 |
22 |
02 |
16 |
21 |
|
15 |
32 |
47 |
44 |
33 |
01 |
Taking class intervals 1 - 10, 11 - 20, ....., 41 - 50; make a frequency table for the above distribution.
The number of chapatis that 30 children in a hostel need at every meal is given below. Make a frequency table for these scores.
3, 2, 2, 3, 4, 5, 4, 3, 4, 5, 2, 3, 4, 3, 2, 5, 4, 4, 4, 3, 3, 2, 2, 2, 3, 4, 3, 2, 3, 2
If a class size is 10 and range is 80 then the number of classes are ___________
The number of times an observation occurs in the given data is called ________
In a frequency distribution with classes 0 – 10, 10 – 20 etc., the size of the class intervals is 10. The lower limit of fourth class is ______.
Tally marks are used to find ______.
If the fifth class interval is 60 – 65, fourth class interval is 55 – 60, then the first-class interval is 45 – 50.
The weights (in kg) of 30 students of a class are:
39, 38, 36, 38, 40, 42, 43, 44, 33, 33, 31, 45, 46, 38, 37, 31, 30, 39, 41, 41, 46, 36, 35, 34, 39, 43, 32, 37, 29, 26.
Prepare a frequency distribution table using one class interval as (30 – 35), 35 not included.
- Which class has the least frequency?
- Which class has the maximum frequency?
Complete the following table:
| Weights (in kg.) |
Tally Marks | Frequency (Number of persons) |
| 40 – 50 | `\cancel(bb|bb|bb|bb|) \cancel(bb|bb|bb|bb|) bb|bb|` | |
| 50 – 60 | `\cancel(bb|bb|bb|bb|) \cancel(bb|bb|bb|bb|) bb|bb|bb|bb|` | |
| 60 – 70 | `\cancel(bb|bb|bb|bb|) bb|` | |
| 70 – 80 | `bb|bb|` | |
| 80 – 90 | `bb|` |
Find the total number of persons whose weights are given in the above table.
